1. Field of the Invention
This invention relates to an apparatus for electrically controlling the throttle valve installed in an internal combustion engine.
2. Description of the Related Art
In the past, the throttle valve incorporated in any vehicle engine has been connected directly to the accelerator pedal through a link mechanism so that the throttle valve is mechanically actuated to displace its position in accordance with the amount of depression of the accelerator pedal by the driver.
Also, recently the apparatus has been proposed in JP-A-56-14834 in which the accelerator pedal position is detected electrically so that the position of the throttle valve is controlled by an electric actuator, e.g., a motor in accordance with the detected accelerator pedal position.
When installing such an apparatus for electrically controlling the throttle valve position in a vehicle engine, however, the apparatus must be constructed to ensure safe running of the vehicle in view of the absence of any mechanical connection between the accelerator pedal and the throttle valve in contrast to the conventional mechanically-actuated throttle valve.